I'm looking at a 1964 Mercury Montclair Marauder. It has a 427 with 4-speed. I'd like to find out if all this is from the factory. It is a Canadian car with the following numbers: 5BB 345 JB and 163C 64L 072721. I've a feeling it was born with a 390. Also, how can I tell if the 427 in there is the right one?

I believe that the MM's did all come with the 427 and 4 speed,however ,I could be wrong.There are several sources that can decode your car.You can start with contacting LMC or Barrett-Jackson or even the local Merc dealership should be able to help. Good Luck!!!